Cooled nozzle segment for combustion turbines



NOV. 19, 1940. V sg pE 2,221,816

cboman uozzm: SEGMENT FOR cpmsus'nofi TURBINE-S I Filed March 17, 1 939 z'sheet-sneet 1 INVEN'i'OR 65am; Stiff/{FEB v ATTORNEYS Nov. 19, 1940.

GOOLED NOZZLE SEGMENT FOR COMBUSTION TURBINES G. SCHAPER Filed March 17, 1939 2 Sheets-Sheet 2 was so INVENTOR GEOEG 501041 52 ATTORNEYS Patented Nov. 19, 1940 UNITED STATES COOLED NOZZLE SEGMENT FOR cosmos- TION renames Georg Schaper,

Muelheim-Ruhr-Brnich, Germany, assignor to Holzwarth Gas Turbine 00., San Francisco, Cali1'., a corporation of Delaware Application March 1'2, 1939, Serial No. 2625427 In Germa March 19, 1938 10 Claims. (c1. so 41) The present invention relates to an improved construction of cooled nozzles and nozzle se ments for combustion turbines, and paiticularly of nozzle segments which consist of cooled in- 5 dividual parts united tothe finished nozzle assembly, and in which the side pieces which between them receive the cooled nozzle sections are likewise cooled.

The impingement of the turbine Wheel blading l in combustion turbines occurs in similar fashion to steam turbines, by way of nozzle groups. These nozzle groups consist of individual nozzles which in cross-section are throughout of more or less rectangular shape, the individual nozzles 15 being separated from each other by intermediate walls. In explosion turbines there generally occur super-critical velocities in these nozzles, so

that the nozzles must be. constructed with a.

widened portion corresponding to the shape sug 20 gested by Laval. This widening brings with it the result that the intermediate walls between the individual nozzles terminate at the gas discharge end in a more or less sharp tip. This construction ofintermediate walls leads to serious difliculties because the walls are contacted upon both sides by combustion gases of rather high temperature and of super-critical velocity. As the heat transmission values increase greatly and in part suddenly with increase of the gas velocities, 30 particularly. in the super-critical region, destru'c tion of the intermediate walls by incandescence and burning can be prevented only by strongly cooling such walls. The intermediate walls must, therefore, be built hollow, as hollow nozzle leaves or sections and be traversedby a cooling agent. However, the circumstances that the highest rate of heat transmission occurs at the tips of the nozzles and that at such tips the space available for cooling agent is smallest, make it extremely Gil 4O dimcult to provide adequate cooling of the nozzle tips, which requires preventing of vaporization with resultant formation of insulating vapor pockets, and attendant deposition of scale.

It is the general-object of the invention to pro 45 vide a nozzle and nozzle segment construction wherein adequate cooling can be secured in a simple and reliable fashion.

According to the present inventiomthe nozzles are composed of sections provided with integral b lateral extensions which are united, as by welding, into a unitary construction; This is advannozzle median lines. The central web of the H-structure is made to act as a baflie and extends for approximately the length of the nozzle and divides the cooling space between each two nozzles into an upper and a lower compartment. 5 The cooling liquid'is introduced at the receiving end of the nozzles and is compelled to-fiow, parallel to the flow of the gases in the nozzles, along the length of the nozzles for a portion of the height of the latter to the tips of the nozzles, where it flows through bores in the webs into the other cooling compartment and then travels in reverse direction toward the receiving end of the nozzles. A body of water or other cooling liquid of large cross-section thus sweeps the sides of the nozzles, the rate of flow at the nozzle tips being sufliciently large to prevent vaporization. The resistance to flow of the cooling agent is r..- duced and danger of scale formation with resulting clogging are eliminated. Further features of the invention will appear from the more detailed description 'hereinbelow. 1

The drawing. shows by way of example a preferred embodiment of the invention. H In said drawings: a

Fig. 1 represents a section through the nozzle group of an explosion turbine inthe circumferential direction and developed in the plane of the drawing;

Fig. 2 shows a radial section through the nozzle arrangement along the line II-II of Fig. 1, the plane of the section containing the turbine axis;

Fig. 3 illustrates a vertical cross-section through the nozzle arrangement according to the lines TIL-III of Fig. 2; v

Fig. 4 shows a vertical, longitudinal section through a nozzle section according to the line IVIV of Fig. 1, while Fig. 5 is a schematic view, partly in section. of an explosion turbine plant having my invention incorporated therein.

The numeral I designates the nozzle valve of an ex losion chamber, upon whose opening the high pressure and highly heated combustion gases generated in the explosion chamber enter by way of the nozzle antechamber 2 into the nozzle channels 3 which are constructed in the manner of a Laval nozzle, and in which the combustion gases are expanded and likewise accelerated. The nozzles 3 are defined by the flanges 4 and 5 of the nozzle sections and alsoby their lateral surfaces 6. The flanges 4, 5 may advantageously be provided by suitable milling of the nozzle section castings. Each two neighbor ng flanges 4 and 5 are united with each other by the welding seams nozzles 3.

liquid and are common to all the nozzles.

The nozzle sections themselves are constructed hollow and are cooled with water which enters through a conduit 8 into a cooling space 9 (see Figs. 2-4) provided below the nozzles, flows through the cooling spaces of each nozzle section, as will be explained below, and reaches the cooling' chamber l arranged above the nozzles, being withdrawn from the chamber Ill by way of conduit H. The chambers 9 and H) are collecting spaces for the infiowlng and outfiowing cooligg shown in Fig. 1, the inlet and outlet points 8 and II for the cooling agent are provided at the lateral ends of the impingement arc containing the nozzle group, the chambers 9 and ill embracing respectively the end members to and Illa and effecting cooling thereof. The chambers 9' and II] are separated from each other by the intermediate wall l2 (see Fig. 3) in order to compel the flow of the cboling agent through the cooling spaces of the nozzle sections, a similar separating wall being provided at the other end of the nozzle assembly.

The cooling space l3 of the nozzle antechamber is fed with hot water or other liquid under pressure through conduit I (Fig. 1) independently of the cooling of the nozzle sections, which is preferably accomplished with a cold medium, such as cold water. The withdrawal of the hot cooling agent for the antechamber occurs at l5.

.As can be. seen with particular clarity from Figs. 3 and 4, the nozzle sections are constructed of approximately H-cross-section, the sides 6 of the nozzles forming the legs of the H, while the horizontal" web 20 acts as an intermediate wall or bailie in the interionof each section dividing each nozzle section I6 I into two'longitudinal spaces or compartments i! and I8. The intermediate wall or baflle 20 has a through passage I9 at the tip of the section whose function will be explained below. The intermediate wall 20 lies approximately at the middle of the height of the nozzle section. It thus supports at the same time the lateral walls 8 of the nozzle section against each other, as can be seen especially from Fig. 3, so that they cannot be altered in their shape under the influence of the combustion gas pressure.

The longitudinal spaces :17 and I 8' of each nozzle section, which are advantageously produced by milling, are covered from above and below by plates 2| and 22, respectively, welded or soldered into the nozzle section body. These cover plates act ,as baiiles in cooperation with the baflle 20 and are'provided with openings for the entry and outflow of the coolingwater at 23 and 24 (Fig. 4). In Fig. 3, the cover plates 2i and 22 can be seen in elevationbecause the section is taken at the point at which the openings or cutouts 23 and 24 lie.

The inflow and outflow collecting spaces 9 and II for the cooling water are constructed of thin and elastic walls 25 and 28. They are welded on the one hand, at 21, with the tips of the maple sections, and on the other hand, at 28, with "the carrier body 28 for the nomle group. In this way the result is attained that the nozzle group can expand freely in every direction upon becoming I heated, so that cracking due to expansion is entirely avoided. A

The mode of operation of the described apparatus is as follows;

The cold cooling water or other agent, charged by conduit 8, fills first of all the inflow collecting space 9 and passes from the latter, by way of the opening 23 in the bottom cover plate or baflle 22, into the longitudinal space l8 of each nozzle section. The nozzle section is thus traversed in the direction of flow of the combusion gases from the rear of the section to the tip of the section by a cooling agent stream which extends for approximately half of the nozzle section height. At 19 there occurs inside of the nozzle section tip the reversal of the cooling agent stream, whereupon longitudinal space i0 is traversed counter-current to the direction of flow of the combustion gases from the tip of the section to the rear thereof by a cooling stream which again occupies approximately half of the nozzle section height. The cooling agent streams discharging at 24 unite in the discharge space l0 and are led ofi by the conduit ll.

In this way not only is every nozzle section efl'ectively traversed by cooling agent along its whole length and height, but the whole quantity of cooling agent is compelled to flow past the inner walls of the nozzle tips and thus effectively cools such tips. The flow cross-sections which are available to the cooling agent in this connection, are comparatively large, so that sufllcient quantities of cooling agent can be conducted through the cooling spaces, whereby not only is an adequate heat withdrawal afforded without any danger of steam formation but also theillustrated in such figure, the chamber being provided with a scavenging air inlet valve 3|, a fuel inlet member 32 andan additional valve 33 for air of higher pressure for eiiecting atomization of a liquid fuel. The outlet valve l controlled, for example, by a hydraulically operated piston moving within a chamber, efl'ects discharge of the high temperature, high pressure gases generated by the explosion, brought about by the spark plugs 35, of an ignitable mixture of air and fuel in the chamber 80, the gases being directed by the nozzles 3 to the first or impulse wheel 36. From the latter they flow, preferably after intermediate equalization of their pressure, to a continuously impinged rotor 81, the exhausted gases being discharged at 38. The guide or stator blades 39 are in heat-conducting connection with the wall 40 forming part of a cooling jacket 4| which is connected by pipe 42 with an evaporator or steam separator 43. high pressure is withdrawn by the conduit 44 and The separated steam of conducted to a high place ofuse, while the hot water is sucked by the pump 45 from the evaporator through the conduit 46 and recharged into the cooling space 4| by way of conduit 41. The water supply is replenished by a feed water pump 48 which is connected with the interior of the evaporator 43 by the pipe 49. The operation of tions assembled to the flnished'nozzle segment and including lateral end pieces which receive between them the nozzle sections, and means providing cooling chambers for said nozzle sections and end pieces, said individual sections haveach other through said flanges by seams runningalong the nozzle median lines.

3. A nozzle segment comprising a plurality of united section at least a number of such sections each comprising a member of H-cross-section having lateral flanges at both sides thereof adapted to be united with similar lateral flanges of an adjoining member to provide a nozzle passageway for a driving medium charged by the nozzles, a casing about the nozzle segment and providing separate collecting spaces for inflowing and outflowing cooling medium, the approximately central web of the H-cross-section forming a separating wall between the two cooling spaces except at the outer tip of the nozzle whereat said wall is provided with an aperture connecting the two spaces, and inlets and outlets for the cooling agent at a point remote from the tip of the nozzle, whereby the entering cooling medium iscompelled to flow along the length of the nozzle for a portion of the height thereoi, is reversed at the tip of the nozzle, and then flowsin the opposite direction along the rest of the height of the nozzle.

4. A nozzle segment comprising 'a plurality of nozzles adapted to charge a hot driving medium, a common jacket for said nozzles, imperforate plates dividing the jacket space into separate spaces for the inflowing and outflowing cooling agent; a baifle arrangement between each pair of nozzles, said bafie arrangement being provided with an aperture connecting the collecting spaces and arranged as to compel the cooling agent to flow along the nozzles in one direction along a portion of the height of the nozzles, to be reversed at the end of the nozzlesand flow in the opposite direction along the length of the nozzles along the remainder of the height thereof.

.5. A nozzle segment as set forth in claim 4,.-

wherein the-baflle arrangement comprises three superposed plates, the top and bottom plate being provided with apertures at one pair of corresponding ends, while the middle plate is provided with a connecting aperture at its end opposite such ends.

6. A nozzle segment as set forth in claim 4, wherein'the nozzles are composed of united sections of approximately H-cross-sections, the middle baflle constituting the web of such H-structure and the top and bottom bailles comprising plates connected to the H-structures' at the .top and bottom thereof.

7. A nozzle segment as set forth in claim 4, wherein the nozzles are composed of united sections of approximately H-cross-sections, themiddle baflle constituting the web of such H-structure and the top and bottom baflles comprising plates bottom thereof. said H-structure including integral lateral flanges forming the body of the nozzles.

8. A jacketed nozzle comprising a tubular passageway for a hot driving medium charged by the nozzle, a jacket about the nozzle, and bafiles at the sides of the nozzle and'within the jacket and provided with openings for the cooling agent so disposed that the latter is compelled to flow along the length of the nozzle for a portion of the height thereof to an end of the nozzle'wherein it is reversed and compelled to flow in the opposite direction along'the rest of the height of the nozzle, and conduits connected to the inlet and outlet sides of the jacket for charging a cooling agent thereto and withdrawing the same there from.

9. A nozzle according to claim 8, wherein, the

' bailies comprise three superposed plates, the middle plate having a through opening at one end thereof and the top and bottom plates having similar openings at their ends remote from sai dle 'plate'having a through opening at-the dis-' charge tip of the nozzle, and the topand bottom plates having similar openings at the opposite connected to the H-structures at the top and end of the nozzle.

GEORG SCHAPER. 

